Patent GB-190517624-A (GB)
Title: Improvements in Automatic Signalling and Train Controlling Systems
Inventor: DAVENPORT HENRY MAC
Filed: 1905-08-31
Granted: 1906-08-02
Abstract: 17,624. Davenport, H. M. Sept. 8, 1904, [date appliedfor under Patents Act, 1901]. Electric railways.-In an automatic mechanical railway signalling system, protection is afforded to the train by a block section extending both for. wardly and rearwardly, which practically travels with the train. Track contact devices in this block are adapted to give signals upon and stop electric trains trespassing within the limits of the block. The train depresses contact levers at each of a series of ten similar pieces of ratchet apparatus or units spaced equally throughout the block, and connected together through cables and spiral springs. Each depression of a contact lever causes the units to move one step in a cycle of ten steps, so that each unit is in a different position in the cycle. The nearest unit is, at each depression of a contact lever, dropped from the chain of units, and another unit is brought into the chain at the front, the units being spaced, say, a thousand feet apart. By modifying the number of ratchet-teeth employed, the number of units in the active chain or block may be modified, and head protection without rear protection, or vice versa, may be obtained by slight modification of each ratchet apparatus. Similar protective devices at points are described. Each ratchet apparatus is contained in a box 20, Fig. 28, fixed at the side of and just below the level of the track rails. Shafts 66, 118, 51 lead therefrom to the track treadle 57, and to the track contact apparatus 115<a>, 115<b>, 116<a>, 116<b>. The ratchet 24, Fig. 1, is mounted on a shaft 23 and is actuated from the track treadle 57 through a link 56, levers 55, 52, a vertically sliding rod 40, a catch bar 41, a pivoted lever 35, a link 36, and two arms 28, 25, mounted loosely on the shaft 23 on each side of the ratchet 24, and carrying a sliding spring-pressed pawl for actuating the ratchet. A detent ratchet 46 is attached to the ratchet 24, and is controlled by a spring detent 47 to limit the motion of the ratchet 24. Three cam surfaces 93, 94, and 102, Figs. 2 and 3, rotated by the ratchet shaft, actuate levers 103, 104, 105 and attached vertically sliding rods 107, 108, 109. The rod 107 operates a shaft 116, Fig. 28, to raise track trip levers 115<a>, 116<a>, and the rod 108 similarly raises trip levers 115<b>, 116<b> through a sleeve 118, the levers 116 , 116<b> merely rotating on the shaft 120 and being connected to the levers 115<a>, 115<b> through rods 122. The vertically sliding rod 109 actuates a shaft 66, Fig. 6, to cause a piece 67 to push toggles 65 out of the straight line and allow a depressed track contact lever 57 to rise after the train has passed a certain distance. Two horizontal sliding rods 70, 71, Fig. 4, are connected through spiral springs 130, 131 to the cables extending between units, and the rod 71 is positively moved to the right hand by a spring-pressed pin 79, Fig. 2, engaging a slot therein and similarly with the rod 70, the motion being obtained by the movement of the piece 72 attached to the ratchetoperating pawl. During each operation of the ratchet, the bars 70, 71 are advanced, and retreated together, but, by means of spring locking-detents, the bar 70 is not moved during the ninth step, and the bar 71 is not moved during the tenth step. In Fig. 2, a unit is shown in the third position, the track lever and the trip lever being down, and similar conditions prevail in position 4. In position 5, the depressible track lever has been raised. Now the unit is operated by the train depressing the track lever, which afterwards remains depressed in position 6, and similar conditions prevail in position 7. In position 8, the track trip lever 116<b>, Fig. 28, is raised, and similarly for position 9. In position 10, the lever 116 is again dropped. If now the unit is at the rear of the chain, its next function is inoperative, and a forward and back movement of the bar 71 is merely produced by the cables, the unit having been thus dropped from the chain. If at the front of the chain, the trip lever 116<a> is raised in position 1, and this condition prevails in position 2. Finally the trip lever 116<a> is lowered in position 3 to complete the cycle. The spiral springs 130,131, Fig. 2, of course cause the actuatiou of each unit in a chain except when the train is actually depressing the track lever. The traincarried apparatus for interaction with the track trip levers comprises a contact-piece 157, Fig. 16, on the stem of a valve 155 in an air-pipe 154 leading to a whistle 163. A pawl on the piece 157 also actuates a ratchet 158 and attached finger 161, which opens a valve 152 in the brake pipe 151 to apply the brakes if the driver has not heeded the whistle signal and the train has proceeded to the second raised trip lever. A second finger 165 on the brake valve may control the electric circuit in electric trains. The two trip levers 116<a>, 116b, Fig. 28, are provided one for each direction of running, and similar trip levers mav be actuated by direct connexion with a disc 202, Fig. 17. on the operating-shaft 201 of switch points. Semaphore, bell, or whistle signals on the track may be operated by the actuation of the units.